search for: psychometr

Dear R-Listers, to measure the psychometric curve of pitch discrimination, one sequentially presents two tones of slightly different pitch to an observer (animal will do), and asks "which is higher". The pschometric curve is the fraction of correct responses plotted against the pitch difference. It passes through 50% (pure guessi...

...t'). It allows the lower bound of the sigmoid to vary slightly from zero, aswell as the upper bound to vary from one. with these two free parameters, the fitted function is less sensitive to noisy data and outliers. Apart from advertising this toolbox I want to ask for possibilities in R to fit psychometric functions, as I would rather use R than matlab. Is there a comparable package specific for psychophysics in R? otherwise: which function would be a good choice? Can I have functionality equal to 'psignifit' with glm() from MASS. I would be grateful for some suggestions of people who have...

Over the last couple of years I have written quite a few R programs for various "psychometric" techniques, and I am regularly updating and expanding what is there. I now have (wholly or partially), or have planned -- gifi package (update to homals on CRAN). Code for multiple correspondence analysis, nonlinear principal component analysis, nonlinear multiset canonical cor...

Version 1.5 of the MiscPsycho package had been uploaded to CRAN (should hit mirrors in a day or so). This package has a set of functions that may be useful for psychometric applications. The package has been updated to include the following: 1) All functions (where appropriate) now use standard formula arguments 2) All functions now use S3 print and summary methods 3) Help files have been substantially improved 4) Where appropriate, functions now use the standard...

Hi, What package would you recommend for analyzing the validity/reliability of multiple choice tests. Doing things such as classical test analysis, factor analysis, item response theory. I've used psychometric (item.exam), MiscPsycho (alpha.Summary), and ltm (rcor.test). MiscPsycho reported the numbers most similar to what I get in SPSS: corrected point biserial correlations, cronbach's alpha. I didn't understand what the psychometric package meant by its "discrimination" and "...

...mpirical data using R. On the R website as well as in the mail archives, I found a lot of help on how to fit a normal density function to empirical data, but unfortunately no advice on how to obtain reasonable estimates of m and sd for a gaussian ogive function. Specifically, I have data from a psychometric function relating the frequency a subject's binary response (stimulus present / absent) to the strength of a physical stimulus. Such data is often modeled using a cumulative gaussian function. I have tried to implement such a fitting algorithm in R, but unfortunately, I was not successful...

Dear list, has anyone written a package/function in R for computing a point- biserial resp. biserial correlation? Thanks in advance Bernd

Please can someone advise me how I can adjust correlations using bonferroni's correction? I am doing manny correlation tests as part of an investigation of the validity/reliability of a psychometric measure. Help would be so appreciated! Cheers, Louise

Dear R-Community, I'm currently trying to find a way to conduct a meta-analysis in R. I would like to analyze data from mostly-cross-sectional survey-studies. The effect sizes would be correlations. The R packages "meta" and "rmeta" are, as far as I can see, set up for analysis with effect sizes for differences (i.e. comparison of the means/odds-ratios of experimental

...d do a correct translation. There must be some more modern ones around, but where? I need the algorithms for a program I have written for exploring structural balance in sociometric group structures. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +------------------------------------------------------------...

Dear all, Is anybody knows simple method for creation norm tables for psychological tests for several groups distinguished by sex and age? best regards, Krzysztof

Dear users, In my psychometric test i have applied logistic regression on my data. My data consists of 50 predictors (22 continuous and 28 categorical) plus a binary response. Using glm(), stepAIC() i didn't get satisfactory result as misclassification rate is too high. I think categorical variables are responsible for t...

...r of installers which make it easy for a programmer to put together all the files needed and place them in the right place. And simeone should get the OpenSuse people to include R in the installation. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +------------------------------------------------------------...

...in R using MASS, nlme, and Matrix. Here is a very brief description. In the monte carlo, I first sample from a multivariate distribution to create data. The data are hypothetical student scores on an achievement test over time and the aim is to examine what happens to standard errors under certain psychometric conditions. The data are then "contaminated" to reflect a certain psychometric problem that occurs in longitudinal analyses of student achievement scores. These data are then analyzed using a linear model to obtain parameter estimates. This is replicated 250 times. For example, the m...

Hello, I'm new to R and work with psychometrics (Item response theory). I was using a package called "cirt" to model a data that contains only 0s, 1s and 9s. The package is basically used for Monte Carlo Markov Chain estimation of parameters and I specified 5000 iterations. The model seems to run fine but when I try to recover odds...

Hi Everyone, I've got a question about data representation. I have some psychometric data with 5 scores for 15 different groups. I've been asked to show some kind of mean plots. The data below is the mean and SD for a given group, unfortunately my employer doesn't want me posting full datasets. :( The groups V,W,X,Y,Z are divided into Bottom, (B), Middle (M) and Top...

...nts are separated by blanks, and that is not optimal for the creation of a table (in the word processing sense). Is there an option to generate tab-separated output in R ? That would solve the problem. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +------------------------------------------------------------...

...package. First question: In the past I've constructed composite variables from questionnaire data by using rowMeans(), and then correlating items with the scale using cor() as an informal check for "bad" items. Over the weekend I decided to take a look at some of the packages in the psychometric task view, to see if there was a way to simplify this process. I looked at several packages, including psychometric, CTT, and psych. I'm interested in hearing from others who need to do this kind of thing frequently. What approach do you use? Do you use one of the packages mentioned above? Ar...

...eason that there are several nice packages containing useful stuff for SNA (Social Network Analysis). Information about packages, web sites, experienced persons in the field, etc. would be very welcome. Tom +----------------------------------------------------------------+ | Tom Backer Johnsen, Psychometrics Unit, Faculty of Psychology | | University of Bergen, Christies gt. 12, N-5015 Bergen, NORWAY | | Tel : +47-5558-9185 Fax : +47-5558-9879 | | Email : backer at psych.uib.no URL : http://www.galton.uib.no/ | +------------------------------------------------------------...

Me and some colleagues are planning to write a textbook together ("Statistics using R") where the target audience for the book is psychologists and students of psychology. We thought that it might be a good idea to use a Wiki when writing the text. Is that a good idea? Does anybody have any experience in that direction? What alternatives are there? The tool (Wiki) would have to be